Northstar Engines and System Technical Discussion Discussion, Drilling and Tapping The Northstar V8......my personal experience so far. in Cadillac Engine Technical Discussion; I was going to post this in Eldorado_Red's thread &quot;97 ETC Headgasket Project&quot; but I decided if someone just wanted ...

Drilling and Tapping The Northstar V8......my personal experience so far.

I was going to post this in Eldorado_Red's thread "97 ETC Headgasket Project" but I decided if someone just wanted to reference just this part, I should make a separate thread.

This is just my opinion and experience so far and nothing more. I'm not being bias or taking side, these are just my personal conclusions.

Once you have decided to remove the engine by whichever method of your liking, you'll eventually come to the crossroad of drilling and tapping the block for repair. Eldorado_Red's and my personal choice is for studs.

I suppose the inserts have to be drilled also, so some of this may apply but since I've been drilling for the studs I'm a bit more familiar in that area that the inserts.

Things you WILL need:

Cutting Fluid......Motor oil or Trans Fluid. I used trans fluid.

Drill with side handle...Mandatory 1/2" variable speed reversible

Drill Bits...... High strength for cutting metal. 1/2 and 17/32.

I have Northstar Performance's Stud kit with it's first design stud plate. The second design "X" plate looks a lot more user friendly, but that could be just "eye" appeal.

Eldorado_Red chose Carroll Custom Cadillac studs. CCC's items came out a bit cheaper for Red, but was missing drills bits, thread locker and the tap. I suppose those items can be sourced rather easily, but I happen to be a one stop shopper so my kit came with those items.

Eldorado_Red and I started to compare the head studs.

I happen to have the "shiny chrome" version of the Northstar Performance head studs. When comparing the studs, (no matter who's version), there is no comparison to the oem head bolt. One thing I did note on CCC's stud was the allen head key dimple on top of each stud to help speed up installation.

The tap needed seems to be the same for either kit, but CCC's kit calls for a bottom tap at one point in the info on the website, but states it my not be necessary in one of the videos.

The tap needed will be 5/8-11 high strength steel. The starter tap has a taper to it to align itself into the hole. The bottom tap, lacks the taper and cuts immediately.

More on that when we cross that bridge.....

DRILLING........

Here's where the fun began......

My personal opinion..........

Tape off the block with DUCT TAPE. The duct tape is more durable, and "forgivable" heaven forbid you start drilling and the drill "jumps" on you. You want to protect the deck surface of the block from any potential harm.

Take the duct tape and cover the deck surface of the block including the holes to be drilled out. Once the deck is completely covered with the duct tape, smooth the duct tape on the deck to make sure the tape sticks to the deck. (Pre cleaning the deck surface before taping is a good idea if not done so already).

Find the head bolt holes with your fingers by running them across the duct tape. The head bolt holes will leave dimples in the duct tape. You will use a single edge razor blade or x-acto knife and cut the dimples out in a circular motion by sticking the edge of the blade into the lip of the hole and trimming away the duct tape. You may need a small flatblade screwdriver to assist in removal of the dimple of tape from the head bolt hole. Do this to all the head bolt holes to be drilled out. Once the holes are exposed you are ready for drilling.

I was a bit skeptical if the holes could be drilled without a guide plate, at this point I can say yes. Yet, the reason for that, I happen to have a bit more experience with these sort of things, but if one were to feel uncomfortable I would advise using some sort of guideplate.

Even with my experience, you still had to get a "feel" on how to drill these holes out.

1. Load the drill with the 1/2 drill bit. Make sure it's TIGHT.
2. DIP the drill bit into the trans fluid/motor oil. You may want to pour a little in the hole to be drilled out.
3. Align the bit with the hole to be drilled and brace yourself firmly. (you'll understand after a few tries). Start the drill just slightly above the hole, don't have the drill going too slow or too fast. You want the bit to "fall" into the hole but cut smoothly at the same time. IF the bit GRABS (it will until you get the feel of it) hit the reverse button to back the bit out. Re oil the bit and hit forward with just enough speed to enter the hole and cut through without "grabbing" on the aluminum block.

4. The 1/2 drill bit is used to "open" the mouth of each hole to some degree. When drilling, keep a steady speed of forward thrust into the hole and enough speed to cut, BUT avoid too slow of a speed for the bit to "grab" the aluminum. While drilling always push in a bit to cut and back out a bit to remove the shavings off the bit. The 1/2" bit WILL reach a point where it "feels" like it "bottoms out". At this point, inspect the hole with a flash light if necessary. Don't force the 1/2 bit any further once you feel it bottoms out, it's supposed to. When you inspect the hole, you should still see some threads left at the very bottom of the hole if you done the procedure correctly.
Do this for all holes.

5. 17/32 drilling. By the time you've loaded this bit in, I feel you should have a "feel" for what's taking place here. You should now have a "feel" for what rpm to cut the aluminum with the drill you are using. You should also have a "feel" on how to get the hole "started" per se' without the bit "grabbing" on initial insertion. The 17/32 bit is used for the final drilling before tapping. Again the procedure used to drill with the 1/2 bit will apply to the 17/32 EXCEPT we're going a little deeper. Lube the bit and the hole if necessary with trans fluid or motor oil. Align the bit above the hole, start the drill. Keep enough speed to fall in, but not to grab. Again, you will acquire a feel for this. Drill into the hole, back out to remove the shavings. With this bit you want to stop and inspect how far down you've gone before you bottom out. The purpose of this bit is to remove the last of the oem threads, and get the hole wide enough for the tapping of the studs. Once you've inspected and can guage how far down you must go to remove the oem threads, make a visual note on the bit or phyiscally mark it with paint. Every bit is different. If your sense of "touch" is just right, you can feel the 17/32 bit "bottom" out also. DO NOT GO ANY FURTHER THAN NECESSARY. Once the traces of the old threads are removed, inspect the hole by blowing out the shavings. You will use this procedure on all of the other holes till completed.

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Side note: Cover any and everything that you don't want aluminum shavings in. This procedure produces ALOT of aluminum shavings. When blowing out the holes, a blow tool with and extended wand is your friend. You will not love the feeling of aluminum hitting your hand as you try to blow the shavings out of the hole......

Nice so far... I would recommend a drill bit depth stop or even a drill with depth rod on it(my 1/2 inch has it and is invaluable when you gotta drill not too deep). Free hand drilling those has gotta have some pucker factor with it. Look forward to the rest of your write up.

It has been said by some that the studs alignment is an issue when you go to drop on the head. You may find some studs are not perfectly aligned with each other. Than you can tweak the stud or enlarge the clearance hole in the head slightly. I would expect the studs to be a bit off if you don't use a guide plate to drill. How far off you can live with is a good question. Let us know how smoothly head drops on when you get there

My biggest fear of drilling. Always get the first 1-2 holes do this, and then I get the feeling and the rest is smooth.

I've used Northstar Performance studs for the second time and the installation is smooth. I just cannot justify drilling the block straight away. Call me chicken, but no thanks, drilling with an alignment plate is nerve racking enough for me. I'd rather go slower, than have me mess up the block.

When tapping, use plenty of lubricant. I used the good ol' trans fluid again. A little messy but I'd rather the tap feel like it's turning like butter than to fight the metal. It still requires a bit of strength.

Like the drilling procedure, turn a few turns, then back out to remove the chips. Blow out the remnants of aluminum and continue tapping.

An oil can with an extended tip will be useful to squirt oil into the hole before tapping. I'd advise dipping the tap into whatever lubricant you decide to use, but from the experience I've had, motor oil or the trans fluid is best. WD 40 or Pb blaster is not going to be thick enough to provide the lubrication need to keep cutting.

After all, you what your tap to stay as sharp and cut as clean as possible.

Pertaining to stud alignment.....

I can tell at least one stud is going to need a little "tweaking". It's the one in the hole that has to be repaired ironically.

I used the headgasket as a test fit after a few holes were tapped. I can tell that hole is going to need a "tweak".

I went back and ran the bottom tap that doesn't come with the Northstar Performance stud kit, bit was recommended by CCC on their website, but not in the videos.

The purpose of the bottom tap for me at least was to clean the threads that I had already cut with the starter tap. After running the bottom tap through all the holes, I blew whatever remanants out with my blow tool.

I plan to go back to the one hole that I had an issue with, seal it off with JB Weld.

We're rolling down hill now......

The three items in the picture will be very valuable during the tapping procedure.

The ratcheting tap wrench, the oil can to squirt oil/trans fluid into the holes and on to the tap and the extended blow tool to keep the debris out of your way while you blow out the holes.

There are hundreds of stud pictures in here, Deville, Seville and the stud maker's websites. Go back through daveyhouse's engine rebuild thread in this forum. Lotsa stud pictures, some of studs that needed 1/8" of tweaking to get in proper alignment.

Nice. I wanted to see just the stud though. Am interested in thread bolt diameter/step?

It's all in the posted websites. Hundreds of times, hundreds of studs.

Here's one of many .......... Tim Carroll's work................. You'll notice that he uses drop-on cylinder head alignment guide pins - Jake's studs have the appropriate studs machined to include the guide. Both suppliers are discussed endlessly in these forums, so anyone with the ability to do an Internet search has access to more pictures. For even more stud pictures, go through the ARP site.